The invention relates to a brake tensioning device for braking a paper roll unwinding on a turret stand of the type utilized in paper converting plants. Typically, the turret stand includes rotating turret arms which carry two rolls of paper. Paper sheeting is unwound from the winding stand for use in a conversion process such as in the manufacture of milk cartons. When the paper on one roll is depleted, the turret arms turn to present a full roll in position for continuous supply of paper to the paper converting process. During the unwinding process, the shaft of the rotating paper roll is braked to maintain a desired tension on the paper sheet being unwound from the roll.
Heretofore, various arrangements of pneumatically actuated disc brake units have been utilized on the turret arms of the unwinding stand to brake and tension the paper roll. Since considerable friction is imparted to the brake unit due to the continuous braking action, these disc brake units have been air or water cooled. A very popular type of water cooled disc brake unit is illustrated in prior art FIG. 2 which is commonly referred to as a Fawick or Wichita clutch brake. One such a brake is manufactured by the Airflex Division of the Eaton Corporation of Cleveland, Ohio as the Airflex WC and WCA clutch brake units.
The disc brake units include brake rotors which are coupled to the rotating shaft of the paper roll either by a spline or by a gear arrangement. Braking discs are carried within the disc brake units which are normally constructed of copper and are moved by pneumatic actuation into engagement with the brake rotors to apply a braking action and tension the paper roll during unwinding. A series of minute water passages are formed in a jacket behind the copper brake disc through which a cooling medium is circulated, such as water, to cool the brake unit. The problem exists that these water passages often become clogged from minerals, rust, corrosion, and other particulate matter. The brake unit then becomes overheated and often melts and is destroyed. In many environments, the life of such a disc brake unit is only several months. Various other attempts to cool such a disc brake unit have not been satisfactory. The problem is complicated by the fact that the paper rolls are mounted on turret arms which must rotate on the unwinding stand. Hence, the disc-type brake unit which is lightweight and simple in construction and in attachment to the turret arm has been utilized in such applications.
Drum type brake units have been utilized on single roll unwinding stands such as shown in U.S. Pat. No. 3,430,738. These type brake units are attached to an associated stationary base on a floor surface. The need to have rotating brake structure is not required in such an arrangement.
Accordingly, an important object of the present invention is to provide a brake unit for a turret unwinding stand for unwinding paper which increased cooling capacity and a reliable cooling system.
Another important object of the present invention is to provide a simplified drum brake which may be rotatably employed on a rotating turret arm of a paper unwinding stand.
Still another important object of the present invention is to provide an apparatus for converting a disc brake to a drum brake unit on a turret arm of a paper unwinding stand.
Still another important object of the present invention is to provide apparatus for converting a disc brake unit to a drum brake unit on a turret arm of a paper unwinding stand in which the drum brake unit has simplified and reliable cooling capacity.